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INTERGALACTIC MEDIUM IN THE ACDM UNIVERSE FROM COSMOLOGICAL SIMULATIONS

  • FENG LONG-LONG (Purple Mountain Observatory) ;
  • HE PING (Department of Physics, University of Arizona) ;
  • FANG LIZHI (Department of Physics, University of Arizona) ;
  • SHU CHI-WANG (Division of Applied Mathematics, Brown University) ;
  • ZHANG MENG-PING (Department of Mathematics, University of Science and Technology of China)
  • Published : 2005.06.01

Abstract

The temperature (T) and entropy (S) fields of baryonic gas, or intergalactic medium (IGM), in the ACDM cosmology are analyzed using simulation samples produced by a hybrid cosmological hydrodynamic/N-body code based on the weighted essentially non-oscillatory scheme. We demonstrate that, in the nonlinear regime, the dynamical similarity between the IGM and dark matter will be broken in the presence of strong shocks in the IGM. The heating and entropy production by the shocks breaks the IGM into multiple phases. The multiphase and non-Gaussianity of the IGM field would be helpful to account for the high-temperature and high-entropy gas observed in groups and clusters with low-temperature IGM observed by Ly$\alpha$ forest lines and the intermittency observed by the spikes of quasi-stellar object's absorption spectrum.

Keywords

cosmology: theory;intergalactic medium;large-scale structure of the universe;methods: numerical

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